My A/C conversion to R134 still working fine after 1year - PeachParts Mercedes-Benz Forum

dc88168 · #1 04-09-2003, 08:48 PM

Last year (on May 12, 2002) I started a thread "I converted my A/C from R12 to R134a for $40 " telling how I made that conversion on my 1985 300D Turbo. Here is the link to that thread:
I converted my A/C from R12 to R134a for $40

There were a lot of people skeptical about this conversion. People suggested that I need to compeltely evacuate and flush the whole system, replace the drier/receiver. I didn't do any of those things.

Now it has been almost a year. I am happy to report to you all that my A/C with this R134 conversion is still working very well.

It is not a "Death Kit". It is a "resurrection" kit to me.

This is a living testimony.

David

________________
1985 300D Turbo

psfred · #2 04-09-2003, 09:03 PM

Its best to completely flush, but not totally necessary if you use the correct oil. The new oil will flow through the system, the old oil (not soluble in the R134) will tend to collect in the crankcase of the compressor, where it is needed.

I did the 220D the other years, still works fine as far as I can tell, since I haven't run it for a while.

Ditto for the Volvo, but I also had to replace the orifice tube in that, and probably will need a new compressor (lots of gray crap in there, often the "gray death compressor syndrome).

Peter

leathermang · #3 04-09-2003, 11:35 PM

Other people : Listen to PSFRED.... if you study AC systems you know why people suggest flushing when you have it open.... it has to do with less cost in the long run.... because you don't know if , for instance, the last reciever dryer 'silica' bag disintegrated and went through the system....etc... yes, you may get lucky... but people who know how the parts are made go to a lot of trouble to do a good flush when the system is open anyway...

#4 04-10-2003, 07:33 AM

DC,

Congratulations, you are definitely living right. Keep your fingers crossed, eleven months of successful operation BEFORE the hot season is here, is not much testimony of its success.

I truly hope you remain lucky and make it through the summer.

Good luck,

dc88168 · #5 04-10-2003, 07:24 PM

Larry, thank you for wishing me luck.

Eventhough I believe miracles do exist in this world, I do not think "luck" has anything to do with the successful conversion of my A/C to R134A.

Last year, during the first month of the conversion, I was indeed keeping my fingers crossed. But after it battled successfully through the long hot summer season, I have no fear now. My A/C works perfectly like a charm. Its cold and cool, man!

I will keep you guys posted if my A/C ever fails for any reason. Otherwise I'll make my "2nd anniversary" progress report to you next year.

David

________________
1985 300D Turbo

leathermang · #6 04-10-2003, 08:05 PM

Am I just being cynical... or is the San Francisco Bay area famous for having a very pleasant and mild climate ? Somewhat the reverse of Texas...

airfoill · #7 04-10-2003, 10:22 PM

Leathermang,

Your absolutely right. I've been to SF in the summer time and it never got over 75 degrees. Wish we had that here in Texas.
R-134 would work flawlessly there.

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo

lrg · #8 04-10-2003, 11:04 PM

This is the land on microclimates. In the city of S.F. the temp almost never goes over 80 (we're too close to the cold Pacific). Drive inland 10 miles and it can be over 100. It makes a BIG difference how far you are from the ocean. Sacramento which is less than a 1 hour drive often is north of 100 in the summer. I live in SF and use my A/C all the time in the summer, just not in SF.

leathermang · #9 04-10-2003, 11:31 PM

For those of you who do not have a Factory Shop manual.... it goes into great detail and has several special tools for doing flush, etc...
Larry and I will never change our minds about doing this according to the book.....the inside of an AC system is a severe work area.... and anything not supposed to be there can really mess up stuff.. and require expensive parts and labor....
I do understand micro climates.. it is amazing how a few miles can make major differences......

Capt Kirk · #10 04-11-2003, 02:05 AM

Quote:

Originally posted by dc88168

Last year, during the first month of the conversion, I was indeed keeping my fingers crossed. But after it battled successfully through the long hot summer season, I have no fear now. My A/C works perfectly like a charm. Its cold and cool, man!

Oooo the SF Bay summers are world renowned for their brutal afternoon highs.

Try Dallas in July/August if you really want a "long hot summer season". There's like no activity in the middle of the day since it's so hot, we wait to do stuff at night (it's not odd to hear lawn mowers going at 9:00 PM).

Either way, good luck this summer, really hope that your A/c keeps going, I know how bad it is to have your A/C crap out at the worst time.

#11 04-11-2003, 08:31 AM

DC,

My worry about your a/c is not whether or not it performs well enough to keep you comfortable. My concern is for the long term health of the unit.

When you do not evacuate and remove moisture, the moisture left behind combines with the refrigerant to form an acid. This acid will eventually eat its way through the aluminum components of your system, particularly the evaporator, which is the most difficult component to change. Depending upon how much moisture is in the system, the acid might take six months to cause problems or six years, but it's like death and taxes, it's gonna happen.

The next problem often invoked by the use of these kits is the fact that the mineral oil is not removed to make room for the oil that will properly circulate with r134. In some cases the mineral oil will just go to the lowest point in system. In an accumulator system such as most GM cars, the excess mineral oil ends up in the bottom of the accumulator and seems to not cause problems. An accumulator is at a different point in the system than a filter drier, the filter has liquid, and it becomes more difficult for it to handle the accumulated oil.

I am very sincere when I wish you good luck with this conversion, but time has shown that the term used on the air conditioning web sites for these kits is correct. They call them "Death Kits." This does not mean death to the driver, it means death to the air conditioner.

Best of luck,

Bruce B · #12 04-29-2003, 10:41 PM

My A/C isn't working but I believe I know it's just an empty system. The service fitting on the fender give a slight hiss when the valve is depressed, so it seems to me that it is holding a little bit of pressure. Compressor runs when L/P switch was jumped, only ran it long enough to see that it works and not noisy, 5 seconds or so. The shop teacher at the High School, also an instuctor at the tech school, is bringing his vaccuum pump and A/C gauges with him tomorrow and we'll hook it up and pull a vaccuum to see if it will hold. Then, and only then, will I go and get the R134 and POE oil for converting and hopefully (fingers crossed) an A/C that will work (getting kinda warm here in Ga).

I know that some may say just add R12 after you do the vaccuum but with it's present expense and not much left out there I may as well convert it now. If the system fails at a later date I think I will be at a better time then to afford a complete conversion.

Thanks to all here (and here) who have helped all of us maintain these fine automobiles.

The Warden · #13 04-29-2003, 11:57 PM

Quote:

Originally posted by leathermang
Am I just being cynical... or is the San Francisco Bay area famous for having a very pleasant and mild climate ? Somewhat the reverse of Texas...

I don't think it's possible to compare to the heat of Texas, but during the summer it does typically get rather hot around here. I'm on the peninsula halfway between San Jose and San Francisco, and will likely see over 100° for at least 2 straight weeks this summer, and mid to high 90's for much of the rest of the summer. Granted, the humidity's nowhere near what you see in Texas

but it does get hot. The San Joaquim Valley, OTOH (central California; Sacramento's at one end and Bakersfield's at the other) gets hot and humid...not quite as bad as Texas, but pretty close.

Granted, for me, a perfect day is 50° and raining cats and dogs

, but still... I actually use the a/c quite often. I still haven't figured out why the car humidifies horribly whenever in EC Mode, so even in the rare occurence when I want heat, the compressor's turning...

The car was converted to 134 before I bought her, so I don't know if it was done "right" or not...I've been planning on doing a 134 conversion on the truck (the R-12 that's in there now has an air pocket or something), but haven't had the $$ to do it right and don't want to blow the compressor...

#14 04-30-2003, 06:58 AM

Bruce,

I would NEVER advocate just putting in R12. You should ABSOLUTELY ENSURE

#15 04-30-2003, 07:03 AM

Bruce,

I would NEVER advocate just putting in R12. You should ABSOLUTELY ENSURE that ANY system is tight and leak free before putting in refrigerant regardless of what refrigerant you are putting in.

My recommendation is that if you are going to convert, do it right. You should remove the compressor and dump out as much of the mineral oil as you can get out. You then should disconnect every fitting and thoroughly flush that hose or component. Replace the filter drier. Put in the correct amount of Ester oil. Reconnect everything using R134 compatible o-rings with Nylog lubricant. Install GOOD conversion fittings, not the aluminum junky ones that you get at the auto supply. Then completely and thoroughly evacuate the system and charge with about 85% of the volume that it specifies for R12.

If you are not going to convert it correctly as described above, you will be MUCH BETTER OFF finding and repairing your leak, evacuating and recharging with R12.

Good luck,